Recently, as air tickets have increasingly gone paperless, instead of showing a paper on which the reservation details are printed to a service agent at the counter, the passengers simply place a two-dimensional code presenting the reservation details stored in a mobile communication terminal such as a cell-phone over a two-dimensional code reader installed at the airport to have various authentication procedures done (for example, see Patent Literature 1).
Patent Literature 1: Unexamined Japanese Patent Application KOKAI Publication No. 2007-241538.